A window shade arrangement for windows in doors of motor vehicles is known from DE 10 05 970. The window shade arrangement described in this patent publication contains a winding shaft that is rotatably supported underneath the window apron and to which one edge of a window shade strip is attached. The opposite edge of the window shade strip is arranged on a pull rod with the window shade strip extending through a slot in the lower window apron when it is unwound. The window shade strip is wound up on the winding shaft with the aid of a spring drive and unwound from the winding shaft with the aid of two linear thrust elements that are sufficiently buckle-proof.
The thrust elements are advanced with the aid of a motor that is accommodated in the door. The thrust elements are driven by means of so-called SUFLEX7 shafts that consist of flexible shaft-like elements with a screw thread on their outer side. Consequently, these shafts represent screw-shaped racks that positively engage with an output gear of a drive motor. Both thrust elements are driven synchronously. In another embodiment disclosed in this publication, the pull rod is guided in guide rails on one or both sides, and the thrust elements run in the guide rail while being guided in a buckle-proof fashion.
It is known that the rear side windows of motor vehicles also can be opened. However, these windows usually cannot be opened over their entire length because the lowered window would otherwise collide with the recess in the door that corresponds to the wheel well. This is the reason why rear side windows are usually divided into an essentially rectangular part and a part that, in the broadest sense, has a generally triangular shape. The window in the rectangular part can be lowered while the window in the triangular part cannot be opened.
In this window shade arrangement, the window shade strip covers both window sections. This type of coverage of both sections requires a certain window geometry. The construction is only suitable for extremely large side windows of very large rear doors. However, one also has to take into account that the interior of such doors is notoriously short of space due to the numerous functions implemented in modern car doors.